JPH0746183B2 - Writing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The following description will be given.

A Industrial Field B Outline of the Invention C Conventional Technology D Problems to be Solved by the Invention E Means for Solving Problems (FIG. 1) F Action G Example (FIGS. 1 and 5) , FIG. 6) H Effect of Invention A Field of Industrial Application This invention relates to a writing device for figures and the like.

B Outline of the Invention The present invention utilizes a response time of laser light scanning when a straight line is drawn between two discontinuous points in a writing device for writing a figure or the like into a cell having a memory function by laser light. The linear interpolation can be performed without performing the interpolation calculation.

C Conventional Technology First, an example of a liquid crystal display device will be described with reference to FIG. In this liquid crystal display device, a display image is written in the liquid crystal cell by irradiating the liquid crystal cell with laser light, and the image is enlarged and projected on a screen by a projection means to display the image. The image has two levels of density, white or black.

And, (10) shows the liquid crystal cell, which, when irradiated with laser light, converts the laser light into heat energy and heats the irradiated part, and this heating causes a phase transition in the liquid crystal. When the alignment state is disturbed and the laser light is stopped, the irradiated part is rapidly cooled, and the disordered alignment state of the liquid crystal remains as it is, so that the irradiated part becomes opaque.

For this reason, the liquid crystal cell (10) is constructed, for example, as shown in FIG. That is, in the figure, (11) is the liquid crystal filled in layers, and the alignment layer (12),
(13) and transparent electrodes (14) and (15) are provided. The electrode (14) is formed on a glass plate (16), and the electrode (15) is a cold filter (17) that reflects laser light.
Is formed on the glass plate (18) with the space between. And
The laser light for writing is emitted from the glass plate (16) side, and the projection light from the projection means is projected from the glass plate (18) side.

Further, in this case, the liquid crystal (11) is a cyanobiphenyl liquid crystal, for example, a mixture of octyl cyanobiphenyl at a ratio of 40 mol% and decyl cyanobiphenyl at a ratio of 60 mol% and absorbs laser light. Sometimes
Depending on the temperature, smectic phase → nematic phase →
It causes an isotropic phase and a phase transition. In addition, for example, the phase transition temperature from the smectic A phase to the nematic phase is 44.8 ° C., and the phase transition temperature from the nematic phase to the isotropic phase is 45.2 ° C.

Furthermore, the liquid crystal (11) contains dyes such as 1,3- (1,4
-Dimethyl-7-isobropyrazulenyl) -cyclobutenediiylium is added to enhance the efficiency of laser light absorption and transmission.

Also, as an example, the effective area of the liquid crystal cell (10) is 20 mm in length.
× width 20 mm, resolution is 2000 pixels vertically × 2000 pixels horizontally.

Further, in FIG. 1, (20) shows a writing means by laser light. The writing means (20) turns on or off the laser light for each pixel according to the display data, and the laser light is turned on and off by the liquid crystal cell (1).
Then, the image is irradiated onto the cell (1) to write an image.

That is, when the display data Ds is taken out from the microcomputer (70) described later, this display data Ds is supplied to the monostable multivibrator (21) to form the write pulse Pw having a pulse width of 2.5 μsec per pixel, This pulse Pw is supplied to the laser diode (23) through the drive circuit (22). This diode (23) is, for example, Ga
This is an AlAs semiconductor laser that outputs near-infrared light with an output of 30 mW and a wavelength of 780 nm.

Therefore, the laser light modulated on or off according to the display data Ds is output from the diode (23), and this laser light is output from the galvano mirror (24) →
Liquid crystal cell (10) through lens (25) → prism (26)
Is supplied to.

Further, in this case, the scanning means (30) scans the liquid crystal cell (10) with laser light. That is, although this scan includes raster scan or vector scan, the digital horizontal address signal Ax and vertical address signal for designating the X coordinate and the Y coordinate of the scan position (laser light irradiation position) from the microcomputer (70). Ay is taken out, these signals Ax and Ay are supplied to the D / A converters (31) and (32) to be analogized, and then the horizontal scanner (35) and the vertical scanner (through the drive circuits (33) and (34)). 36), so that the galvanometer mirror (24) is driven in the horizontal and vertical directions by these scanners (35) and (36), and the laser light is delivered to the coordinates of the liquid crystal cell (10) designated by the signals Ax and Ay. Is irradiated. In this example, since the resolution of the liquid crystal cell (10) is 2000 pixels in the vertical direction and 2000 pixels in the horizontal direction, the signal A
x and Ay are 11 bits each.

Further, (41) shows an erase circuit, which is a microcomputer (7
Controlled by (0), an alternating voltage ER of a predetermined level is taken out, and this voltage ER is applied to the electrodes (14) and (14) of the liquid crystal cell (10).
It is supplied to (15) and erased. However, this erasing includes a full erasing in which the entire surface of the cell (10) is erased and a partial erasing in which only a part is erased, and these are performed as shown in the following table.

In the partial erasing, the low voltage erasing voltage ER is supplied to the entire surface of the cell (10) and the laser light is irradiated only to the portion to be erased.

Further, (42) represents a temperature control circuit, whereby the liquid crystal cell (10) is held (biased) at 43.3 ° C., which is 1.5 ° C. lower than the first phase transition temperature of 44.8 ° C. in a steady state, and therefore, the steady state. At times, the liquid crystal (11) is kept in the smectic A phase state.

Further, (50) indicates a projection means, by which the image on the liquid crystal cell (10) is enlarged and projected on the screen (60).
That is, projection light is taken out from a light source, for example, a 150 W halogen lamp (51), and this projection light is converted into an infrared filter (52) → condenser lens (53) → ultraviolet filter (5
4) → mirror (55) → the liquid crystal cell (10) is irradiated through the optical path of the lens (56), and the light transmitted through the cell (10) is projected through the prism (26) onto the screen (60) by the projection lens (57). To be done. Therefore, the image written in the cell (10) is enlarged and displayed on the screen (58).

In this example, the screen (58) is the display screen of the projection means (50) and at the same time, the tablet board (61) of the tablet (60) is integrated. It is constructed as shown in FIG. That is, in the figure, (59) is a flat plate,
Moreover, the transparent glass plate has a projection glass side surface as a ground glass surface (59A) to form a display screen (58), and a surface opposite to the ground glass surface (59A) is transparent. In addition, a plurality of striped electrodes (63) are arranged separately from each other in the horizontal direction. Also, (6
4) is a flat plate and a transparent glass plate.
A plurality of transparent and stripe-shaped electrodes (65) are arranged on the surface opposite to 9) separately from each other in the vertical direction. The glass plates (59) and (64) are in close contact with each other with an insulating layer (not shown) in between to form a transparent tablet board (61). The glass plates (61), (6
The thickness of 4) is, for example, 1 mm and 3 mm, respectively, and the size thereof, that is, the size of the screen (58) and the tablet board (61) is, for example, A4 size.

Further, (66) is a tablet pen, in which the electrode (pen tip) is insulated from the grip, and a voltage (scan pulse) is supplied to the electrodes (63) and (65) of the tablet board (61). At that time, it is supposed to catch the electric field.

Also, (70) indicates a microcomputer that performs various controls, and (7)
1) is the CPU, (72) is the ROM in which the control program is written, (73) is the work area RAM, (74) is the input port, (75) and (76) are the output ports, These circuits (72) to (76) are connected to the CPU (7
1) connected to. In addition, the CPU (71) has a bus (7
A full keyboard (77) and a display memory (78) are connected through 9), and a floppy disk device (82) is connected through an FDC (81). In this case, the display data written in the liquid crystal cell (10) is accessed in the memory (78), and for example, the cell (10) has a capacity of 2000 bits vertically × 2000 bits horizontally.

Then, when the keyboard (77) is operated to enter the writing mode, ER = 0 is set, and a tablet-type scan pulse is formed in the microcomputer (70). This pulse is transmitted through the port (75) to the electrode (14), It is sequentially supplied to (15) and scanning is performed. Then, at this time, when the tablet pen (66) is applied to the glass plate (64), the scan pulse is detected by the tablet pen (66) and is taken into the microcomputer (70) through the port (74).

Then, in the microcomputer (70), the tablet pen (6
The scan pulse detected by 6) is the electrode (14),
It is determined which electrode in (15) is being scanned, and the coordinates indicated by the tablet pen (66) are obtained from this determination result, and the address signals Ax, Ay are calculated according to these coordinates. The generated signals Ax and Ay are supplied to the D / A converters (31) and (32) through the port (76), and the display data Ds are supplied from the port (76) to the multivibrator (21). Therefore, the corresponding pixel (coordinates) of the liquid crystal cell (10) is irradiated with laser light to make this pixel opaque, and this is projected onto the screen (58) by the projection means (50), so that the screen (58) A black dot is displayed at the position where the pen (66) is applied.

At this time, the bit corresponding to the coordinate in the memory (78) is set to "1".

In this way, when drawing is performed on the tablet board (61) with the tablet pen (66), dots are written in the corresponding portion of the cell (10) and the pen (6
The trajectory of 6) is displayed. At the same time, the corresponding bit in the memory (78) is also set to "1".

Further, when the keyboard (77) is operated to enter the erase mode, the erase voltage is supplied to the cell (10) to erase the entire surface or the designated portion of the pen (66). At this time, the corresponding bit in the memory (78) is also reset to "0".

When the keyboard (77) is operated when the drawing is completed, the display data of the memory (78) at this time is saved in the floppy disk device (82). When the display data of the floppy disk device (82) is designated to be loaded, the display data is loaded into the memory (78) and the display data is sequentially read and written into the cell (10). The image saved in the floppy disk device (82) is displayed on the screen (58).
To be played.

Thus, according to this display device, drawing can be performed.

(Reference: Specification and Drawing of Japanese Patent Application No. 59-278509) D Problems to be Solved by the Invention However, as described above, drawing is performed while inputting coordinates using a coordinate input device such as a tablet (60). If the sample rate of inputting coordinates with the tablet (60) is
Normally, it is limited to 110 points / second, so if you move the tablet pen (66) quickly, the entered coordinates will become discontinuous. Therefore, when only the input coordinates are written in the liquid crystal cell (10), the locus drawn by the pen (66) is not a solid line but a broken line.

Therefore, in general, the area between the starting point and the ending point of the locus of the pen (66) is interpolated by calculation, and the coordinates corresponding to the straight line between the starting point and the ending point are also written for each pixel so that the solid line is displayed. ing.

However, in this method, if the interpolation calculation is performed by software, the software becomes complicated and takes time. Also, if it is done by hardware, a special IC for graphics is required, which results in a significant cost increase.

The present invention is intended to solve such a problem.

By the way, the above-mentioned galvanometer mirror (24) and scanners (35) and (36) are specifically configured, for example, as shown in FIG. That is, the laser diode (2
Laser light (23L) from 3) is collimated by the collimator lens (23L).
X) (24X) and Y after collimated by A)
It is sequentially reflected by the mirror (24Y) and is focused on the liquid crystal cell (10) through a lens (25) and a prism (26), which is not shown in this figure.

In this case, the mirrors (24X) and (24Y) are rotatably supported by the galvanometers (35A) and (36A) to form the scanners (35) and (36). Therefore, when the galvanometer (35A) is driven by the address signal Ax, the mirror (24X) rotates, which causes the laser beam (23L) to scan the cell (10) in the horizontal direction and drive the galvanometer (36A). Then, the mirror (24Y) rotates, whereby the laser light (23L) scans the cell (10) in the vertical direction.

As described above, since the scanning of the laser light on the cell (10) is generally performed by mechanical means, the scanning of the laser light is delayed.

Therefore, the address signals Ax and Ay designating the irradiation position of the laser light and the display data Ds supplied to the laser diode (23) have the timings shown in FIG. That is, as shown in FIG. A, first, at time t ₀ , the address signals Ax, Ay from the port (76) change from the coordinates (Xi, Yj) up to that point to the target coordinates (Xm, Yn). . Then, the galvanometer mirror (35A) is driven by this, the mirror (24X) is rotated, and the X coordinate that should be irradiated by the laser light gradually changes from the coordinate Xi to the coordinate Xm as shown in FIG. Then, it stabilizes at the new coordinate Xm at a certain time t ₁ . At the same time, the Y coordinate which should be irradiated by the laser light is also stabilized at the new coordinate Yn.

Then, at time t ₁ , display data Ds is output from the port (76) as shown in FIG.
Is supplied to the multivibrator (21) to be a write pulse Pw having a pulse width Tw of 2.5 μsec as shown in FIG. 7D, and this pulse Pw is supplied to the laser diode (23).

Therefore, dots are displayed at the coordinates (Xm, Yn) on the screen (58).

E Means for Solving Problems As described above, even if the address outputs Ax and Ay change at the time t ₀ , the coordinates to be irradiated by the laser light are immediately changed to the new coordinates (X
Instead of becoming m, Yn), the new coordinates (Xm, Yn) become after the response period (t _{0 to} t ₁ ). Then, during the period (t _{0 to} t ₁ ), the coordinates to be irradiated by the laser light are the old coordinates (Xi, Y
It changes linearly from j) to the new coordinates (Xm, Yn).

The present invention pays attention to such a point, and two discontinuous points (X
When a straight line is drawn between (i, Yj) and (Xm, Yn), the write pulse Pw is supplied to the laser diode (23) during the laser light scan response time (t _{0 to} t ₁ ). .

F action Linear interpolation is performed without performing interpolation calculation.

G Embodiment In FIG. 1, a ROM (72) is provided with a routine (90) as shown in FIG. 6, for example, and two discontinuous points (Xi, Y) are provided.
When drawing a straight line between j) and (Xm, Yn), this routine (90) is executed by the CPU (71).

That is, the routine (90) starts from step (91), and at step (92), two points (Xi, Yj), (Xm,
The number N of dots displayed between Yn) is calculated by N = K ₁ D + K ₂ (i) D: Linear distance between two points K ₁ K ₂ : Constant, and then the number of dots in step (93) It is checked whether N is smaller than the upper limit Nu.
This is because when the distance D is large, the signal at time t ₀ is
The change in Ax or Ay becomes large, and as a result, as shown in FIG. 5B, the change in the coordinates during the response period (t _{0 to} t ₁ ) becomes abrupt, resulting in a response period (t _{0 to} t ₁ ). This is because the equation (i) becomes unsuitable when becomes shorter and the equation (i) is ignored when the distance D is larger than a certain amount.

When N <Nu, the process of the CPU (71) proceeds from step (93) to step (94), and this step (94)
Pulse for displaying N dots at
The period Tp of Pw (Fig. 5F) is obtained, and then the step (9
In step 5), the display data Ds is output from the port (76) as shown in FIG. 5E, and then the period Tp is delayed in step (96), and then the value N becomes “1” in step (97). Is decremented, and it is checked in step (98) whether the value N is “0”, N
When ≠ 0, the process returns to step (95). Therefore, N
= To until 0, step (95) - (98) will be is repeated, from the port (76) as shown in FIG. 5 E, N pieces with a period Tp in the period (t ₀ ~t ₁₎ The data Ds of is output. Then, when N = 0, the process proceeds to step (98).
To step (99) to end this routine (90).

Then, from the port (76), as shown in FIG.
Is output, the multi-vibrator (21) outputs N write pulses Pw at a period Tp in the period (t _{0 to} t ₁ ) as shown in FIG. F, and the laser light is modulated by the pulse Pw. At the same time, since the irradiation coordinates of the laser light are linearly moving from the old coordinates (Xi, Yj) to the new coordinates (Xm, Yn), these coordinates (Xi, Yj), ( Xm, Y
A straight line is displayed between n).

When the number of dots N is equal to or larger than the upper limit value Nu (N ≧ Nu), the process proceeds from step (93) to step (100) and the conventional display is performed.

Thus, according to the present invention, it is possible to draw a straight line between two discontinuous points. In this case, in particular, according to the present invention, linear interpolation is performed using the delay in the response time of the laser light scan. Therefore, it does not require complicated software and does not take much time. further,
Without needing a special IC for graphics,
Does not increase costs.

Although the coordinate input device is a tablet in the above description, it may be a mouse or the like.

H Effect of the Invention According to the present invention, since the linear interpolation is performed by utilizing the delay in the response time of the laser light scan, complicated software is not required and it does not take time. Furthermore, no special IC for graphics is required, and the cost does not increase.

[Brief description of drawings]

FIG. 1 is a system diagram of an example of the present invention, and FIGS. 2 to 6 are diagrams for explaining this. (10) is a liquid crystal cell, (20) is a writing means, (30) is a scanning means, (50) is a projection means, (60) is a tablet,
(70) is a microcomputer.

Claims (1)

[Claims] 1. A tablet comprising: a cell on which writing is performed; a writing means for writing on the cell with a laser beam; a scanning means for controlling a writing coordinate of the laser beam on the cell; and a tablet. , The coordinate value of each of the two points designated by the tablet is calculated, the distance between the two points is calculated from the coordinate values, and this distance is a predetermined value. When the distance is smaller, the scanning means writes on the cell corresponding to the two points, and when the distance is larger than a predetermined value, the writing on the cell corresponding to the two points is performed. Writing device characterized by prohibition.